wall functions
 

Hello everybody
i have a question about wall functions in Fluent:
1- Is wall function applied only for the first near wall cell, or for the whole boundary layer???
2- To calculate the velociy values using wall functions, we need to have the friction velocities. Anyone can tell me how Fluent calculate the friction velocity?
Thanks

i think that you know becouse don't see the velocity profile near a wall with your simulation. this depend on the mesh that aren't sufficiently accurete, so i'm sorry but you take gambit and near the wall you reduce a size of mesh.
i understend your question?
i hope useful
bye
p.s. for how cumpute the value, fluent use the differential equations and trasform it in algebric equation approsimate that function with a difference (as such as the definition of derivative in mathematics) and the residual is the error that fluent introduced in this operation.

1. B.C. only for the first cell, in the boundary layer Fluent calculate according to 'wall functions'
about second question i not understand what u want to compute and what you meen by "friction velocity"

Thank u comrade
u responded to my second question too :)
friction velocity is uf (u+=u/uf)
regards